Biogas decarbonization process and device for synchronous recovery of liquid CO2 by gas membrane separation

Abstract

A marsh gas decarbonizing process capable of synchronously recycling liquid CO2 through gas membrane separation comprises the following steps:1) primarily purifying raw gas of marsh gas through a primary gas separation membrane, and controlling gas at the retentate side through a secondary gas separation membrane to reach quality standards of natural gas; 2) pressurizing the gas at the permeation side of the primary gas separation membrane through a CO2 compressor, passing the pressurized gas through a rectifying tower, collecting the liquid CO2 at the bottom of the rectifying tower, returning tail gas on the top of the rectifying tower and the gas at the retentate side of the secondary gas separation membrane to the primary gas separation membrane, and purifying again so as to improve the recycling rate of CH4. The invention further discloses a marsh gas decarbonizing device capable of synchronously recycling the liquid CO2 through the gas membrane separation.

Description

technical field [0001] The invention relates to biogas produced by anaerobic fermentation or landfill gas produced by landfills, the main impurity being CO 2 The decarbonization and purification production process of coalbed methane, etc., more specifically involves a gas membrane separation and synchronous recovery of liquid CO 2 biogas decarbonization process. [0002] The invention also relates to a method for synchronous recovery of liquid CO in gas membrane separation 2 biogas decarbonization device. Background technique [0003] The main components of biogas are methane and CO 2 , by removing CO from biogas 2 It can effectively increase the calorific value of biogas to expand the application range of biogas. CH 4 The greenhouse effect of CO is 2 21 times of , thus increasing CH 4 A high recovery rate is critical to reducing greenhouse gas emissions. At present, the methods of biogas decarbonization and purification are all through the change of operating condi...

AI Technical Summary

Problems solved by technology

[0007] Chinese patent 201110031702.2 proposes to absorb CO in biogas with tap water 2 and H 2 S so as to realize the method of methane purification, but it does not involve the recycling of water, and there is no advantage from the large-scale biogas purification process

From the principle of membrane separation, it is difficult to avoid CH 4 Loss through the membrane to the permeate side

Images